In the electrochemical plating field, it is often desirable to strip plating from plated metals. However, many of the known stripping agents are costly and/or difficult to control. In addition, many known stripping agents are hazardous.
For example, the use of cadmium plating for steel parts has long been known. However, the recent categorization of cadmium as a carcinogen has led industry to seek an alternative plating for cadmium. Zinc/nickel alloy plating has been seen as a useful alternative to cadmium plating. Unfortunately, processes using zinc/nickel alloy plating have had their potential utility as a cadmium replacement impacted by the lack of a reliable and convenient stripping solution for the removal of the zinc/nickel alloy plating from substrates, including steel substrates.
Known cadmium plating stripping agents (from steel substrates) typically undergo a chemical reaction that imparts atomic hydrogen to the steel substrate. This is due to the use of ammonium nitrate (which generates hydrogen) in cadmium stripping solutions. The hydrogen-rich environment is not desirable for plated steel being “stripped” of its plating, causing hydrogen-based embrittlement of the steel base metal substrate. Such embrittlement makes the stripped steel unusable for many structurally dependent end uses, and further complicates steel processing, as the embrittled steel must undergo remedial processes such as, for example, baking to become useful for contemplated end uses.
The use of acid-type stripping agents in plating (and stripping) processes also imparts hydrogen to the stripping environment (stripping tanks), resulting in the same above-discussed embrittlement issues relative to the underlying steel base metal. In addition, acid-type stripping agents will further undesirably attack steel substrates.
A useful and effective solution that would act to remove or “strip” plating such as, for example, zinc/nickel alloy plating from metal substrate surfaces, without embrittling or attacking the metal substrate, and would allow for the reuse of the substrate, and eliminate the need for processes to remediate the metal substrates (e.g. baking procedures), would otherwise be highly advantageous.